One thing that is I feel missed about uptime percentage when compared to on premise uptime is when the downtime occurs. Its far more impactful if its in the middle of the working day or during the busy period of shopping. A store that goes offline in the middle of black friday or in the run up to Christmas is harmed a lot more than some down time on a Sunday night/Monday morning at 3am.

One thing I have noted over time is a lot of these AWS, Azure et el downtimes is they occur in the middle of everyones day, millions of people are impacted by them. Same with github its getting in the way of work. Whereas when we hosted services on our own equipment the downtime was usually out of main hours. The percentages are in many ways the wrong measure of downtime because hours aren't equal in impact to businesses.